Early detection of breast cancer and other types of cancer is typically an important factor to successfully treat cancer. Ultrasound tomography is a promising imaging modality that has the potential to improve medical imaging of tissue for screening and diagnosis purposes compared to conventional imaging techniques. For instance, mammography is the current standard tool for breast screening, but involves ionizing radiation that precludes frequent imaging, plus mammography has a low sensitivity for detection of cancer in patients with dense breast tissue, which leads to a relatively high false negative rate. As another example, magnetic resonance imaging (MRI) is prohibitively expensive for routine and also has limited accessibility.
However, the quality of ultrasound ray tomography relies largely on the accuracy of the picked absolute time-of-flights, or the measured overall time it takes for an acoustic wave to travel between an ultrasound emitter-receiver pair. Furthermore, standard ultrasound ray tomography depends heavily on accurate and clear onset of signal arrivals, but typically contain systematic errors or other sources of uncertainty. Current ultrasound ray tomography methods may use the time-of-flight acoustic data to create an acoustic speed reconstructions, but inaccuracy of picked time-of-flights downgrades the quality of the resulting images (for example, the resulting reconstructions may not capture particular distinct characteristics of the tissue), which has the potential to greatly affect screening and diagnosis conclusions. Thus, there is a need in the medical imaging field to create an improved system and method for imaging a volume of tissue. This invention provides such an improved system and method for imaging a volume of tissue.